Changes

==Plot introduction==

==Plot introduction==

The first crew to land on [[Mars]] discovers signs of microbial [[Extraterrestrial life|life]]--and might be dealing with a threat from much larger forms of life.

The first crew to land on [[Mars]] discovers signs of microbial [[Extraterrestrial life|life]]—and might be dealing with a threat from much larger forms of life.

===Explanation of the novel's title===

===Explanation of the novel's title===

The Mars mission crew consists of only four [[Astronaut|astronauts]], but suffer repeated mishaps that strongly suggest the presence of a fifth man on Mars with them.

The Mars mission crew consists of only four [[astronaut]]s, but suffer repeated mishaps that strongly suggest the presence of a fifth man on Mars with them.

==Plot summary==

==Plot summary==